Suggest closest contestant name when converting a message to completion

Gemfile

@@ -45,6 +45,7 @@ gem "dartsass-rails"
 gem "bootstrap", "~> 5.3.3"
 gem "friendly_id", "~> 5.5.0"
 gem "csv"
+gem "damerau-levenshtein"
 
 group :development, :test do
   # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem

Gemfile.lock

@@ -104,6 +104,7 @@ GEM
     connection_pool (2.5.3)
     crass (1.0.6)
     csv (3.3.5)
+    damerau-levenshtein (1.3.3)
     dartsass-rails (0.5.1)
       railties (>= 6.0.0)
       sass-embedded (~> 1.63)
@@ -438,6 +439,7 @@ DEPENDENCIES
   brakeman
   capybara
   csv
+  damerau-levenshtein
   dartsass-rails
   debug
   factory_bot_rails

app/controllers/messages_controller.rb

@@ -74,7 +74,6 @@ class MessagesController < ApplicationController
     @action_name = t("helpers.buttons.back")
     @action_path = contest_path(@contest)
 
-    @message = Message.find(params[:message_id])
     @completion = Completion.new()
     @completion.display_time_from_start = @message.display_time
 
@@ -96,7 +95,19 @@ class MessagesController < ApplicationController
   end
 
   def set_data
-    @contestants = @contest.contestants.order(:name)
+    @message = Message.find(params[:message_id])
     @puzzles = @contest.puzzles
+    @contestants = @contest.contestants.order(:name)
+    if @contestants.size > 0
+      @closest_contestant = @contestants.first
+      closest_distance = 10000
+      @contestants.each do |contestant|
+        distance = DamerauLevenshtein.distance(@message.author, contestant.name)
+        if distance < closest_distance
+          closest_distance = distance
+          @closest_contestant = contestant
+        end
+      end
+    end
   end
 end

app/views/completions/_form.html.slim

@@ -22,6 +22,10 @@
       .form-floating
         = form.select :contestant_id, @contestants.map { |contestant| [contestant.form_name, contestant.id] }, {}, class: "form-select"
         = form.label :contestant_id
+  - if @closest_contestant
+    javascript:
+      el = document.querySelector('select[name="completion[contestant_id]"]');
+      el.value = "#{@closest_contestant.id}"
   - if @puzzles.size > 1
     .row.mb-3
       .col